1. Field of the Invention
This specification relates to a mobile terminal capable of optimizing vibration in response to a touch input through a vibration frequency sweeping and vibration power control method thereof.
2. Background of the Invention
Mobile terminals may be configured to perform various functions, for example, data and voice communication, capturing images or video, storing voice, reproducing music files via a speaker system, displaying images or video and the like. Some of mobile terminals may include an additional function of playing games, and other mobile terminals may be implemented as multimedia players. In addition, in recent time, mobile terminals can receive broadcast or multicast signals to allow viewing of video or television programs.
Furthermore, many efforts are undergoing to support or enhance various functions of such mobile terminals. Such many efforts include not only changes and improvement of structural components implementing a mobile terminal but also software or hardware improvement.
Among others, a touch function of the mobile terminal is designed for a user unfamiliar to button/key input using a touch screen to conveniently execute operations of the mobile terminal. In recent time, the touch function is becoming an important function of the terminal together with a user interface (UI), in addition to a simple input function. Hence, as the touch function is further applied to the mobile terminal in various forms, development of appropriate UIs is more needed.
In general, the mobile terminal generates vibration using a vibration motor. Examples of vibration motors being used include a coin type motor, a brush type motor, a linear type motor, a pan type motor and the like. Among others, the linear motor has an advantage in view of reaching a maximum vibration (power) within a short time at a specific fixed frequency as compared to other vibration motors, so it is built in the mobile terminal for use.
However, similar to other vibration motors, the linear motor uses the fixed operational frequency, so it has disadvantages of increasing an overlap amount or improving vibration only by a mechanical supplementation. That is, a damper (or double-sided tape) has been attached onto upper and lower portions of the linear motor (i.e., the mechanical supplementation) or the damper has been more closely adhered onto the linear motor to improve the vibration by increasing a horizontal vibration effect more than a longitudinal vibration effect (i.e., the change in the overlap amount).
Consequently, since the mechanical supplementation and/or the adjustment of the overlap amount are fixed at the moment of fabricating mobile terminals, the mobile terminals exhibit slight difference of vibration power unless those mobile terminals are completely the same as each other. As a result, when a user purchases a mobile terminal having the linear motor, whether the corresponding mobile terminal exhibits good vibration or not depends on chance, and there is no proper way to change the bad vibration by software configuration. Hence, the related art mobile terminal has a problem that it cannot guarantee stable vibration for a user according to a characteristic of a single product (i.e., individual mobile terminal).
Also, for the related art mobile terminal having the linear motor, in order to ensure a constant vibration, a driving voltage of the linear motor should always be increased more than a specific level. The increase in the driving voltage causes a battery lifespan to be reduced.